docs: def csstext_to_pairs(csstext):
      """
      csstext_to_pairs takes css text and make it to list of
      tuple of key,value.
      """
      # The lock is required to avoid ``cssutils`` concurrency
      # issues documented in issue #65
      with csstext_to_pairs._lock:
          return sorted(
              [
                  (prop.name.strip(), format_value(prop))
                  for prop in cssutils.parseStyle(csstext)
              ],
              key=itemgetter(0),
          )